From: "Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>
To: "pxv3620@rit.edu" <pxv3620@rit.edu>, "dev@dpdk.org" <dev@dpdk.org>
Cc: Minseok Kwon <mxkvcs@rit.edu>
Subject: Re: [dpdk-dev] cuckoo hash in dpdk
Date: Wed, 23 Aug 2017 18:28:29 +0000 [thread overview]
Message-ID: <3EB4FA525960D640B5BDFFD6A3D891267BA9E6FA@IRSMSX108.ger.corp.intel.com> (raw)
In-Reply-To: <CANp7S22_QwiMVuQaPLzesMH=XoxUZMbXFPZpPu7zvdGuL1uVHQ@mail.gmail.com>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Pragash
> Vijayaragavan
> Sent: Wednesday, August 23, 2017 3:16 PM
> To: dev@dpdk.org
> Cc: Minseok Kwon <mxkvcs@rit.edu>
> Subject: [dpdk-dev] cuckoo hash in dpdk
>
> Hi,
>
> I got the chance to look at the cuckoo hash used in dpdk and have a query.
>
> would using division and modulo operations be slower than bitwise
> operations on RTE_HASH_BUCKET_ENTRIES, specially since
> RTE_HASH_BUCKET_ENTRIES is a power of 2.
> For example, to do a modulo we can do a "AND" operation on
> (RTE_HASH_BUCKET_ENTRIES - 1), which might be faster. We did a cuckoo
> filter for VPP and doing this gave a slight improvement in speed.
> Is there any particular reason its done this way.
>
> Sorry if i am being wrong in any way, i was just curious.
>
> Thanks,
>
> Pragash Vijayaragavan
> Grad Student at Rochester Institute of Technology
> email : pxv3620@rit.edu
> ph : 585 764 4662
Bitwise AND typically takes 1 cycle on any CPU, while modulo takes dozens of cycles.
next prev parent reply other threads:[~2017-08-23 18:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-23 14:15 Pragash Vijayaragavan
2017-08-23 18:28 ` Dumitrescu, Cristian [this message]
2017-08-23 20:20 ` Pragash Vijayaragavan
2017-08-23 20:39 ` Pragash Vijayaragavan
2017-08-24 14:53 ` Andriy Berestovskyy
2017-08-24 18:54 ` Pragash Vijayaragavan
2017-08-25 9:00 ` Andriy Berestovskyy
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